Effect of Mastectomy on Milk Fever, Energy, and Vitamins A, E, and Beta-Carotene Status at Parturition
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J. Dairy Sci. 85:1427–1436 American Dairy Science Association, 2002. Effect of Mastectomy on Milk Fever, Energy, and Vitamins A, E, and β-Carotene Status at Parturition1 Jesse P. Goff, Kayoko Kimura, and Ronald L. Horst National Animal Disease Center, USDA-ARS, Ames, IA 50010 ABSTRACT INTRODUCTION The objective of this study was to compare blood pro- The dairy cow commonly experiences an abrupt files of intact and mastectomized periparturient cows change in her metabolic status around the time she to discriminate those metabolic changes associated calves and begins lactating. These changes include neg- with the act of parturition from the metabolic changes ative energy, calcium, and protein balance as well as caused by lactation. Mastectomized and intact cows had profound changes in circulating steroid hormone, min- similar increases in plasma estrogens and cortisol con- eral, and antioxidant vitamin profiles. These changes centrations around the time of calving. Mastectomy could be caused by the metabolic challenge of milk pro- eliminated hypocalcemia and the rise in 9,13-di-cis reti- duction, or could be caused by the act of parturition. A noic acid observed in intact cows. Mastectomy reduced comparison of metabolic profiles in periparturient cows but did not eliminate decreases in plasma phosphorus, mastectomized in midgestation, so the metabolic de- α-tocopherol, and β-carotene associated with parturi- mands of lactation are eliminated, but the changes asso- tion in intact cows, suggesting the mammary gland is ciated with the act of parturition remain and, in peri- not the sole factor affecting plasma concentrations of parturient intact cows, might allow resolution of the these compounds. Dry matter intake was similar in cause of these metabolic changes. both groups before calving. The day of calving, dry mat- The typical dairy cow is in negative energy balance ter intake was lower in intact cows than in mastectom- in early lactation. Removal of the udder of a dairy cow ized cows, but after calving the mastectomized cows should remove the demand for energy and reduce body exhibited a pronounced decline in feed intake. Plasma fat mobilization, without affecting hormone secretion nonesterified fatty acid (NEFA) concentrations rose associated with the act of parturition. If the hormonal rapidly in intact cows at calving and did not return to events associated with parturition, especially the rise baseline level for > 10 d. In contrast, NEFA concentra- in plasma cortisol and estrogen concentrations, insti- tions in mastectomized cow plasma rose moderately at gate the mobilization of body fat stores, body fat mobili- calving and returned to baseline level 1 to 2 d after zation should occur even in the mastectomized cow. calving. This study provides evidence that hypocal- Hypocalcemia is a common sequel of parturition in cemia in the cow is solely a result of the calcium drain the dairy cow. The production of colostrum, with its of lactation. The act of parturition affects blood phos- high calcium content, is generally believed to remove phorus, dry matter intake, and NEFA concentration calcium from the blood faster than it can be replaced independent of the effect of lactation. from bone calcium stores or dietary calcium. However, (Key words: mastectomy, hypocalcemia, milk fever, Stott (1968) reported that older cows that had suffered retinoic acid) milk fever in the past and that were then mastectom- ized, developed severe hypocalcemia at the next calving, = Abbreviation key: RA retinoic acid. suggesting that perhaps milk production was not the only cause of hypocalcemia in the periparturient dairy cow. In part, this experiment was designed to repeat this observation. Received October 12, 2001. Accepted January 15, 2002. Plasma vitamins A and E concentrations decline Corresponding author: J. P. Goff; e-mail: [email protected]. around the time of calving (Goff and Stabel, 1990; Weiss 1Names are necessary to report factually on available data; how- et al., 1992). Colostrum contains substantial amounts ever, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of of these two compounds. However, it is also possible the product to the exclusion of others that may be suitable. that these two vitamins show substantial losses as a 1427 1428 GOFFETAL. result of increased utilization. If colostrum production tion of the left side of the udder to the cleft between were the only cause of the reduction in vitamins A and the anterior quarters of the udder, exposing the lateral E observed at parturition, then the removal of the udder ligament of the udder. The lateral ligament was incised, of cows should prevent any decline in blood concentra- and blunt dissection exposed the left external pudendal tions of these vitamins at calving. artery and vein which were individually ligated. The Vitamin A is the precursor to a variety of retinoic left subcutaneous abdominal vein (milk vein) was simi- acid (RA) derivatives with varying biological roles in larly isolated and ligated. The left side of the udder cell differentiation. The enzyme, 9-cis-Retinol-dehydro- was dissected free of the abdominal wall, revealing the genase, catalyzes the oxidation of 9-cis-retinol to 9-cis- medial suspensory ligament of the udder. This was in- retinaldehyde. This is the first enzymatic step needed cised along its length about 8 to 10 cm from the abdomi- for 9-cis-retinoic acid formation (el Akawi and Napoli, nal wall. Blunt dissection revealed the right external 1994). Mertz et al. (1997) surveyed several human tis- pudendal artery and vein and subcutaneous abdominal sues and found that 9-cis retinol-dehydrogenase mRNA vein, which were ligated. The entire mammary gland expression was most abundant in the mammary gland. could then be dissected free of the abdominal wall. The Interestingly, the major retinoic acid in plasma of peri- skin on the right side of the udder was incised so as to parturient cows was determined to be 9,13-di-cis-RA leave enough skin to cover the defect left after the udder (Horst et al., 1995a). Plasma 9,13-di-cis-RA concentra- was removed. A Penrose drain was placed the entire tion increased markedly at the onset of lactation and length of the incision and was removed 2 d after sur- remained elevated in early lactation. Mastectomy gery. The skin edges were brought together and an- might eliminate a major in vivo source of 9-cis retinol- chored to the underlying connective tissues. Supportive dehydrogenase and reduce production of 9-cis-retinoic treatment included 20 L of physiological saline admin- acid and its metabolite, 9,13-di-cis-retinoic acid. istered intravenously during surgery, prophylactic an- tibiotics for 7 d after surgery, and 1.1 mg of flunixine meglumine/kg of BW per day for 3 d after surgery for MATERIALS AND METHODS analgesia. In most cows, the skin edges healed, with a Animals moderate degree of granulation within 6 wk. In three cows, the skin incision sutures became infected and Older Jersey cows (6 to 9 yr of age), in their third or required draining the wound, followed by granulation greater pregnancy, were used in this study. The 10 cows of the skin to close the defect. In these cows, complete chosen for mastectomy were all cows that would have closure of the skin wound required up to 12 wk. All cows been culled because they had had severe mastitis or were fully recovered at least 1 mo before parturition. had not become pregnant until late into lactation. Cows were nonlactating for at least 3 wk before surgery, and Diet surgery was performed when the cows were 3 to 5 mo pregnant. This allowed a minimum of 3 mo for recovery Cows were fed a poor quality alfalfa-grass hay ad from the surgery before calving. Eight intact cows of libitum, with access to a mineral salt block until 3 wk similar age to the mastectomized cows and expected to before the expected date of parturition. At that time, calve about the same time as the mastectomized cows cows were placed on a TMR consisting of alfalfa hay were used as controls. The intact control cows were and a grain mix. The diet was purposely high in dietary cations (Table 1). The diet supplied 125,000 IU of sup- nonlactating for 8 to 9 wk before calving and were fed plemental retinyl palmitate and 2200 IU of supplemen- the same diets as the mastectomized cows for the last tal DL-α-tocopheryl-acetate per day. The pre-calving 8 wk of gestation. No sham surgery was performed on diet was 15.8% crude protein, 1.52 Mcal Nel/kg, 37% the intact animals. The intact cows were dry-treated NDF, 1.19% calcium, 0.4% phosphorus, and 0.5% mag- for mastitis prevention and vaccinated against common nesium. It had a cation-anion difference [(sodium + pot- infectious diseases and coliform mastitis during the dry assim) * (chloride + sulfur)] of + 443 mEq/kg diet DM. period. All procedures performed on these cows were The intact cows were fed an additional 1.8 kg/day of a approved by the Animal Care and Use Committee of 17.2% protein corn-soybean meal-oats concentrate in the National Animal Disease Center. the milking parlor after calving. The mastectomized cows remained on the same pre-calving ration follow- Surgery ing calving. Cows were placed in right lateral recumbency under general anesthesia throughout the surgery. An incision Blood Samples was made in the skin approximately half way between Daily plasma samples for metabolic profile assays the teats and the abdominal wall from the caudal por- were collected from each cow beginning 2 wk before Journal of Dairy Science Vol.